Stability of schwertmannite and jarosite in an acidic landscape: Prolonged field incubation

摘要: Abstract Schwertmannite and jarosite are two of the main secondary iron(III) minerals commonly found in acidic, iron sulfate-rich environments such as acid mine drainage coastal sulfate soils (CASS). Both exert major influence on water soil quality these environments. While there many studies conducted stability under controlled laboratory conditions, behaviour schwertmannite field conditions factors influencing their have not been investigated directly. In present study, we examined net transformation introduced samples incubated a typical acidic CASS environment. Pure (synthetic) were exposed to chemical regimes: 1) aerobic–acidic column 2) anaerobic–neutral sediment Changes mineralogy, micromorphology, composition monitored over period 12 months. suspended buried sediments transformed goethite by end 12 months but more quickly anoxic, reducing sediments. However, at much faster rate than those reported for aerobic laboratory. Jarosite both was also slower schwertmannite. Dissimilatory microbial reduction Fe 2 + -catalysed likely played role accelerating The sensitive hydrological fluctuations relation antecedent rainfall. comparison, sediment's geochemistry relatively stable consequently dissolution this environment appreciably affected variable hydrology.